/* probe-example.c
 *
 * Connects two functions to marker call sites.
 *
 * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 *
 * This file is released under the GPLv2.
 * See the file COPYING for more details.
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/marker.h>
#include <asm/atomic.h>

struct probe_data {
	const char *name;
	const char *format;
	marker_probe_func *probe_func;
};

static int logger_pid=0;
module_param(logger_pid, int, S_IRUGO);

void probe_subsystem_event(void *probe_data, void *call_data,
	const char *format, va_list *args)
{	
	/* Declare args */
       
	const char *print_name; 
        int print_pid;
	long long print_time;
	unsigned int print_size;

	/* Assign args */
	print_name = va_arg(*args,typeof(print_name));
	print_pid = va_arg(*args, typeof(print_pid));
        print_time = va_arg(*args, typeof(print_time));
	print_size = va_arg(*args, typeof(print_size));
	/* Call printk */
	printk(KERN_INFO "DATAPATH: %s: Pid=%i Time=%lli Size of read= %u\n", print_name, print_pid, print_time, print_size);

	/* or count, check rights, serialize data in a buffer */
}

atomic_t eventb_count = ATOMIC_INIT(0);

void probe_subsystem_eventb(void *probe_data, void *call_data,
	const char *format, va_list *args)
{
	/* Increment counter */
	atomic_inc(&eventb_count);
}

static struct probe_data probe_array[] =
{
	{	.name = "sys_read_start",
		.format = "%s %i %lli %u",
		.probe_func = probe_subsystem_event },
	{       .name = "sys_read_end",
                .format = "%s %i %lli %u",
                .probe_func = probe_subsystem_event },
	{       .name = "vfs_read_start",
                .format = "%s %i %lli %u",
                .probe_func = probe_subsystem_event },
	{       .name = "do_sync_read_start",
                .format = "%s %i %lli %u",
                .probe_func = probe_subsystem_event },
	{       .name = "generic_file_aio_read_start",
                .format = "%s %i %lli %u",
                .probe_func = probe_subsystem_event },
};

static int __init probe_init(void)
{
	int result;
	int i;
	printk(KERN_INFO "STARTING PROBE\n");
	marker_set_logger(logger_pid);
	for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
		result = marker_probe_register(probe_array[i].name,
				probe_array[i].format,
				probe_array[i].probe_func, &probe_array[i]);
		if (result)
			printk(KERN_INFO "Unable to register probe %s\n",
				probe_array[i].name);
	}
	return 0;
}

static void __exit probe_fini(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(probe_array); i++)
		marker_probe_unregister(probe_array[i].name,
			probe_array[i].probe_func, &probe_array[i]);
	printk(KERN_INFO "Number of event b : %u\n",
			atomic_read(&eventb_count));
}

module_init(probe_init);
module_exit(probe_fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("SUBSYSTEM Probe");
